1. Field of the Invention
The present invention relates to a process for producing 2-benzoyloxyacetaldehyde derivatives that are useful as fine chemicals such as pharmaceutical preparations and agricultural chemicals and as intermediates thereof.
2. Description of the Related Art
A process for producing a 2-benzoyloxyacetaldehyde derivative has been reported in J. Org. Chem. 1977, 42, 2900-2902. This process comprises the steps of converting chloroacetaldehyde diethyl acetal into 2-hydroxyacetaldehyde diethyl acetal by treating with an aqueous potassium hydroxide solution at high temperatures under pressure (under a load), and converting the resulting compound into 2-benzoyloxyacetaldehyde diethyl acetal by treating with benzoyl chloride. The process, however, cannot be said as an industrially advantageous process, since the first step of converting the chlorine substituent into hydroxyl group requires pressurization, the high-yield isolation of resulting 2-hydroxyacetaldehyde diethyl acetal requires complicated procedures, and the preparation of the target compound from the starting material, chloroacetaldehyde diethyl acetal, requires two stage reactions including conversion of the chlorine substituent into hydroxyl group, and condensation with benzoyl chloride.
Bioorg. Med. Chem., 1996, 2071-2080 and PCT International Publication Number WO 03/051298 disclose a process for preparing a 2-benzoyloxyacetaldehyde derivative by allowing a halogenated acetaldehyde dimethyl acetal to react with potassium benzoate in the presence of dichlorohexyl-18-crown-6-ether. This process can yield the target compound under normal pressure in one step, is more advantageous than the above-mentioned process, but is still not industrially advantageous, because dichlorohexyl-18-crown-6-ether for use in the reaction is hardly available. In addition, according to the process, the condensation between a benzoate and a chloroacetaldehyde acetal derivative yields the target compound only in a low yield, although the condensation between the benzoate and a bromoacetaldehyde acetal derivative proceeds relatively smoothly.